I’ve been eating differently and the results have been dramatic, one the few seemingly “miraculous” events in my life. It has been a diet of my own devising and I cover it the next article. But one cornerstone is that I stopped eating all starches and sugars. My theory is that a calorie is not really a calorie - that calories eaten have very little to do with calories of weight gain.
Conventional wisdom is that weight is ruled by energy balance. Calories consumed minus calories expended equals calories of fat gain. It is called conservation of energy, or sometimes the first law of thermodynamics. And it is beyond dispute that conservation of energy applies to all systems, including our bodies. Nevertheless, the conventional wisdom about calories, while very popular, is very wrong. At least that is my unpopular idea.
Of course, it is not really a new idea and it is not really mine. I learned something about the Atkins diet many years ago. Though it seemed to be about meat consumption and ketosis, which sounded expensive and maybe dangerous. More recently, I had heard that starchy high-glycemic foods may play a role in weight gain. I had even heard of the South Beach diet, but only as a name, since I am way too uncool to take a Miami fad seriously. But oil-drenched salads sounded better to me than all meat all the time, so I tried what turns out to be a modification of the South Beach approach. And the results have been rather spectacular. Not only have I lost six inches off my waist size, but while doing so I have been much less hungry than before.
It turns out that my calorie fallacy theory is also not as unpopular as I originally thought. A little research turns up no end of blogs and web sites devoted to the evils of eating carbohydrates. Of course, most sources are not nearly as respectable as the experts still recommending low-fat calorie restricted diets. Low-carb proponents seem to fall into two categories: 1) weight loss doctors, who presumably make their living by offering new and possibly faddish diets, and 2) bloggers such as myself who have performed an experiment with a very small sample size (just themselves) and who are evangelizing their weight-loss results. I am suspicious of evangelists, not because they are insincere, but because it seems we humans have an inclination to believe highly preposterous things. I call that our “religious gene” and may write more about it someday. In the mean time, it is interesting that I and a bunch of other people have lost weight by cutting out carbs. And it is interesting that a growing number of MDs recommend such diets. But it is not totally convincing.
Which is why I view Gary Taubes’ new book, Good Calories, Bad Calories, as important. Here is a well respected science writer who is calmly saying the same things and who was apparently already skinny to start. It is the book I would like to have written. Mr. Taubes definitely got there first, though I learned of his book several months into my own experiment.
This article is not a review or summary of Taubes’ book. Instead, it is my attempt to summarize the what is wrong with low-fat low-calorie diets and why they remain so popular with most experts. For it seems there are a number of interesting reasons for this calorie fallacy.
The Food Pyramid
The USDA introduced the “Food Pyramid” in 1992, which encouraged us to consume lots of breads and starches. And it groups fats with sugars as substances to be avoided. At least they got the sugars right.
As children, we were often told that refined sugar caused tooth decay and that sweets were fattening. Actually it seems to me that sugars are a subtle poison, insidious because unlike other poisons, they taste great. That is because our metabolism is mostly sugar-based. We literally burn sugar in the form of glucose as our primary fuel. But sugar is dangerous. Sugar is like oxygen, a necessary evil that is both powerful and corrosive. Sugar combines with oxygen to power our metabolism, and unregulated we might literally burn up. Nature seems to have devised insulin to control our sugar, just as it devised hemoglobin to keep raw oxygen out of our bodies. But too much refined sugar overwhelms the mechanism, resulting in obesity and diabetes.
Refined grains and starches are really sugars and are almost as bad. Yet that is just what the US government has been encouraging us to consume. The USDA recommended diet is literally based on grains and starches.
It is probably not coincidental that obesity rose from 12% of the US residents in 1991 to 21% in 2001. Today more than 30% of Americans are obese and 64% overweight. It is easy to assume that we eat too much, or maybe that we eat too much fat, which has over twice as many calories per ounce as other foods. The reality is that we eat too much starch and sugar, and possibly not enough fats.
The popular low fat and high grain diet recommended by the USDA and most nutrition experts is very probably killing us, not just from the complications of obesity, but also from type 2 diabetes. Diabetes is a growing modern epidemic, with the number of American diabetics doubling in the the last twenty years, and with even higher increases among children and teens. The same mechanisms that cause starches and sugars to turn to fat also encourage insulin resistance and type 2 diabetes. The USDA food pyramid is literally killing Americans.
Warning: Avoid the following if you have any puns sensitivity.
Q. So you believe the government is trying to kill us?
A. Governments don’t kill people. People kill people.
A. Bureaucrats (which is Greek for “rulers in a chest of drawers”).
Q. Still, surely you favor government control?
A. The constitution guarantees us the right to bear governments.
Fats make you fat, right? Fats have twice as many calories as other foods per weight and even more per volume. They are associated with cholesterol and heart disease. Indeed. cholesterol is a kind of fat. Reduce your fat intake and you will dramatically cut down on your calories and loose weight. Plus your heart will be healthier. So goes the conventional wisdom.
But this conventional wisdom is mostly wrong. Consume less fat and you will become hungry and eat more, especially if you replace the fat with starches and sugars (which is exactly what most “low fat” processed foods do). Plus fat is difficult for the body to digest. It cannot be directly absorbed into the intestines and must be broken down first. Eating fats does not necessarily make you fat.
Once in the blood stream, fatty acids can indeed be stored in body fat (called adiposal tissue). But this only happens when you have also eaten carbohydrates. Fat cells contain triglycerides, which are more complex and larger than the fatty acids circulating in our blood. While fatty acids can enter or exit adiposal fat cells, triglycerides are trapped inside. To store fat, fatty acids in your blood must be converted to triglycerides, a process which occurs in the fat cell. This requires alpha glycerol phosphate, which is derived from sugar alcohol. It also requires insulin, a hormone necessary to catalyze the conversion. But insulin is only present when secreted by the pancreas to help digest carbohydrates. Without insulin, fatty acids cannot be trapped as triglycerides inside fat cells. Without insulin, we cannot gain weight.
So in the end, it looks like stored fat results from eating carbohydrates and not from eating fats. The carbohydrates we eat are converted to glucose in the blood stream. Glucose can be burned in muscles or converted to fatty acids in the blood. The fats you eat also end up as fatty acids in the blood. And those fatty acids, whether from glucose or digested fats, can be converted to fat tissue, but only with elevated insulin levels that come from eating carbohydrates. Without carbs, we cannot gain weight.
Not that carbohydrates are the only cause of weight gain. There are probably numerous other factors, including genetic disposition. But the other factors are mostly beyond our control. Reduced calorie diets are within our control and sometimes result in weight loss, though it is usually quite temporary and may happen because carbs were reduced along with overall calories. So it appears that eating less carbohydrates is by far the most effective thing we can do to control weight gain.
To me it looks as if fats are the evolutionary result for our need to store excess carbohydrates. Nature invented them because they are energy dense. Remember that petroleum and other types of oil are just kinds of fat. So without carbohydrates there probably would not be any fats in the first place, at least in an evolutionary sense. Nature probably came up with a highly efficient mechanisms for converting the carbohydrates we eat into stored fat and for converting that stored fat back into useful energy (for most cells have machinery for burning both glucose and fatty acids). But I would bet converting digested fats to stored fat is less efficient. If nothing else, it seems to depend on one somewhat expendable organ, the gall bladder. Fats are not easily soluble and so are not easily digested. Storing dietary fat as adiposal fat is not something evolution probably cares much about and so is probably not as easy as we might imagine. My guess is that eating fat probably cannot make you as fat as eating carbs, even with lots of insulin to help the process.
The fat fallacy is so entrenched that even when we know better, we are often still in its thrall. Some medical experts are beginning to question whether eating carbohydrates might be the real cause of most weight gain. But almost inevitably, these newly enlightened experts end up recommending a low-fat low-carb diet. Low fat still comes first, possibly for reasons that no longer seem valid.
Cholesterol and Heart Disease
There is also controversy over cholesterol and heart disease. Maybe the biggest reason most doctors and other experts have been so opposed to dietary fat is the possible link between dietary fat and heart disease. That high fat presumably would also lead to obesity, because fats are so calorie dense, was just icing on their cake (so to speak). It appears that few actually bothered to test the obesity assumption, which led to decades of what now looks like very bad advice. And now there are rumblings that they may not have even been right about the heart disease.
The arguments against cholesterol and saturated fats is mostly beyond the scope of this article. But it seems that a lot of the antipathy against high-fat diets is because they are widely believed to increase your risk of cardiovascular disease. Cholesterol artery deposits are often associated with such disease and cholesterol is a kind of fat. Though I’ve long thought it may be wrong to assume that cholesterol deposits have much to do with dietary cholesterol, since the liver synthesizes cholesterol even if we don’t eat it.
Saturated vegetable fats, which were developed early in the twentieth century by Crisco® and then margarine makers who needed solids rather than oils, were thought to be a health risk by the 1970’s. After all, cholesterol is mostly saturated. Natural animal fats like butter, lard and dairy products tend to be saturated and so we were told to avoid them.
But there has long been a vocal minority claiming that butter is much healthier than margarine, because it has more nutrients and also because processed poly unsaturated fats are prone to become rancid through oxidation and so may be carcinogenic. Recently a very large NIH sponsored study of post-menopausal women (the group most likely to develop heart disease and cancer) tested the conventional low-fat high-fiber wisdom and found essentially no health benefits. The group consuming much less fat and almost no saturated fat was just as likely to get cancer or heart disease. And they did not even loose weight compared to women who ate normally, even though they consumed hundreds of calories less daily for a number of years.
Lately the new conventional wisdom is that trans fats are the problem. They seem to increase “bad” LDLs (low density lipoproteins), which distribute cholesterol from the liver, at the expense of “good” high-density HDLs, which are thought to help clear cholesterol from tissues. Maybe so. But trans fats are a type of unsaturated fat, exactly what what was supposed to be “good” before.
So I am not sure whether the eating fats or the wrong fats might increase our risk of heart disease and maybe cancer. There are seemingly credible researchers who claim this is mostly a myth. If they are right, then we have another fat fallacy, making popular opinion just about 100% wrong when it comes to dietary fat. Not only does a low fat diet cause obesity (a very serious disease by itself), it may not be better for the heart and may be somewhat carcinogenic if it involves cooking with poly unsaturated fats.
Personally, I try to eat mostly olive oil, since the Mediterranean diet, involving olive oil, red wine and fish, seems to keep Mediterranean populations healthier on a relatively high fat diet.
The Role of Insulin
But let’s return to insulin, that linchpin of fat storage. Fortunately, we know a lot about insulin from treating diabetes. And fortunately it appears that we can throttle back our insulin by avoiding carbohydrates and probably just by avoiding starches and other high-glycemic carbs.
Insulin is secreted only when we eat carbohydrates and indeed its role is mostly to help digest those carbohydrates and temporarily store them in the liver as glycogen. Its role in forming triglycerides in fat cells seems to be a secondary but related effect, probably also intended to help store excess digested carbs.
Moreover, it seems that insulin is released mostly when we eat refined carbohydrates like sugar and flour. Other more complex carbohydrates combined with fiber do not elevate our insulin nearly as much. And eating leafy vegetables like broccoli and lettuce have almost no effect on insulin.
Actually, what we know is the “glycemic index” of various foods, a measurement of how much our blood glucose rises when we eat them. But apparently, insulin levels always rise in lock step with glucose blood sugar. So the same glycemic index information widely distributed for diabetic diets is also very useful for weight control, where we want to control insulin more than glucose.
So it appears that all carbohydrates are not the same when it comes to insulin and weight gain. There are “good” carbs and “bad” carbs, the good ones being fibrous vegetables. Apparently digested fiber dramatically slows down the conversion of the associate carbohydrates into blood glucose and so does not trigger fat storage. And it may be good for cardiovascular health as well. The bad carbs are starches and sugars, especially when highly refined. To be safe, I personally avoid all grains in any form that could conceivably be made into bread. That means that I am not eating high-fiber grains and breads that may have a low enough glycemic index. Avoiding sugar, bread or anything vaguely bread-like is an an easy rule to follow and works well for me. I also avoid fruits because they contain sugar, though fructose seems to have a pretty low glycemic index.
Hunger and the Brain
There is another good reason for avoiding refined sugars and starches. Eating them is likely to make you hungry. These foods rapidly raise your blood sugar, which is exactly why they raise your insulin, triggering fat storage. But what goes up must come down, and a few hours later a drop in blood glucose is likely to trigger hunger.
It seems likely that dropping blood sugar is the body’s primary hunger signal. The brain is particularly sensitive to blood glucose, since unlike most other cells, neurons can only burn glucose and cannot use fatty acids for fuel. So the brain must be acutely aware of glucose levels, especially since stored glucose can only be held by the liver for a limited time. The brain needs a fairly constant supply of dietary sugars and dropping blood glucose tends to trigger strong feelings of hunger. In effect, glucose is a psycho-active drug.
Eating refined carbs tends to make us more hungry than ever and we tend to eat again and again, trying to keep our blood sugar at a high level. For it is the drop in sugar that we notice, not the absolute level. So we eat more and store more fat.
You may notice that I am being inconsistent here. I have been arguing that the number of calories we consume is not relevant to whether we gain weight. But here I am arguing that we are less hungry and eat less if we stay away from sugars and starches. Who cares if the extra calories don’t matter? I suppose it does not hurt to hedge our bets. Moreover, the two effects do not happen in isolation. So hunger and increased eating tends to happen when our insulin level is raised, leading to a destructive cycle of ever increasing fat storage. Obesity and maybe diabetes are the possible result.
If fat and calories are not the villains we thought, where do all those excess calories go? After all, conservation of energy must still apply. Stored fat is a form of energy because we can burn the fat and extract the calories of heat.
Our bodies probably just burn off excess energy as waste heat. For some reason, nutritionists have long assumed that the human body is a near perfect energy machine, perfectly converting foods to either useful activity or stored fat. Indeed biology is lot more efficient than human-engineered machinery. But we are definitely not perfect. Some people just don’t get fat not matter how much they eat and how little they exercise. And animal breeders have long known that weight is mostly a matter of genetics, not food and exercise. As Taubes points out, different breeds of cattle can have quite different weight set points, though they are all just sedentary cows eating pretty much the same grass.
Rather than being something like the atomic-powered Delorian in Back to the Future, perfectly converting all fuels to pure energy, it seems more likely that we are at least a little like those wells in Texas where waste natural gas is burned while extracting oil. My guess is that our bodies simply turn up the thermostat a little and burn off excess food when needed. In fact, I know we do since I often grow warm to the point of sweating at the end of a heavy meal.
As Taubes also argues, weight gain (or loss) might might be the cause rather than the effect. So entrenched is the calorie fallacy, it is quite hard to grasp this at first. But suppose our bodies decide to gain weight for whatever reason, possibly due to insulin, genetics or some other cause. As a result of that weight gain, our bodies might then adjust the amount of food we eat to compensate. Or we might automatically adjust our metabolic rate or physical activity to burn the excess energy. Such automatic adjustment of energy in or out in response energy gains seems much much more likely than the other way round. It would be extremely difficult to adjust our food intake precisely enough to maintain constant weight year after year. There must be an automated adjustment that regulates energy and weight for variations in diet, since humans are not all that consistent in our eating habits.
That our bodies might not cope well with refined starches and sugars makes sense given what we know of our heritage. For we evolved as hunters and gatherers. It was only about 10,000 years ago that humans discovered agriculture and the joys of cultivated grains. That was probably the single most important discovery of all time and was the great enabler of modern civilization.
Cultivation changed our diet dramatically and probably for the worse. Agriculture could support many more people, but not as well. Our hunter/gatherer ancestors probably did not number over 100,000 worldwide. With the coming of farming, food became a lot more available and large city-based populations could be fed, but not as nutritionally. The average height of humans significantly decreased with civilization and it is only modern protein-rich diets within the last century that have enabled us to grow as tall as prehistoric people. Eating too much grain stunts your growth. I have also argued that carbohydrates make you overweight, but not always if there is barely enough and not always if they are not highly processed. Only in modern times have we been rich enough with enough technology to produce lots of pure sugar and starch.
The diet of human hunters before civilization was probably very low in simple carbohydrates. And that explains why are bodies are so ill-equipped to handle them now. We are evolved to eat meats and maybe scavenged vegetables and fruits. Highly processed carbs were never available and so our bodies cannot cope with them. Unlike most poisons, they taste good, because they are indeed too much of a good thing.
Some even question whether ancient humans ate many vegetables at all. They recommend a diet that is 100% protein and fat as being most natural. These zero carbs proponents argue that vegetables have poisons put there by nature to discourage herbivores. That is true. Most spices as well as coffee and other foods are really mild irritants that we have learned to like. I for one do like them and am not yet convinced that all fibrous vegetables can really be that bad for us. If nothing else, lettuce makes a great substrate for my olive oil. Rightly or wrongly, the zero-carb crowd reminds me of children who refuse to eat their vegetables.
It is interesting to consider why the calorie fallacy ever happened. Conspiracy theories usually seem contrived, and I do not believe government or the medical establishment has been actively dishonest about calories and diet.
We have already mentioned one big reason: conservation of energy. The first law of thermodynamics argues for the calorie approach and any suggestion that calories are wrong strikes scientists as energy voodoo.
Plus grain is the essential invention of human civilization and so criticizing carbs goes against our grain (if you will pardon the pun).
Another factor is the bad reputation that meat has, given that killing animals can seem a lot like murder. After all, vegetarians cannot easily follow a low-carb diet.
My guess is that the biggest reason behind the calorie fallacy is that Americans invented the calorie as used to measure food energy. Taubes points out that as early as the 1920’s German researchers, the preeminent nutritionists of their day, had decided that weight gain could not be explained by calories or measured by food calorimeters, then a new American invention. In effect, the American calorie approach was at war with the German fat storage explanation. And it probably did not help that Americans invented Wonder Bread® around that time. American nutrition theory won twenty years latter, not because it was right, but because the academic argument was subsumed in World War II. After the war, German theories fell from favor and were forgotten. American nutritional science remained firmly attached to our beloved calorie.
Professor O. W. Atwater developed extremely sensitive calorimeters in Connecticut at Wesleyan University around the turn of the twentieth century. They were used to measure the energy value of various foods. Room sized devices could measure total human energy input and output with amazing accuracy. So the calorie was born.
The famous Atwater 4, 9, 4 values were landmarks in the study of nutrition. Atwater determined that on average, one gram of carbohydrate or protein yields four calories of energy, while the same weight of oil yields nine calories. Actually, the units involved are kilo calories (Kcal), the amount of energy needed to heat one kilogram of water by one degree Celsius. Amazingly, those same 4, 9, 4 values are mostly still used today. Food suppliers can simply look up calories given the weights of the constituent ingredients.
The Fallacy of Names
Another cause of the calorie fallacy is the problem of names. We Homo Sapiens are good at naming things. So good that names are critical to how we think. Probably our facility at language, our ability to think with words, is what makes humans smarter than other animals. So maybe a better name for our species might be Homo Nomen, the naming people. Names are important because they allow us to think in the abstract and to relate diverse things and ideas.
But names can also be a weakness because sometimes they lead to bad comparisons. Nuclear bombs are bad, so we tend reject anything with “nuclear” in its name. Nuclear power is an unpopular idea for another day, but it is a lot more sustainable and better for the environment than burning fossil fuels. I would bet that a lot of our problems with nuclear power hinge on the word “nuclear” rather than reality. Medical Nuclear Magnetic Resonance (NMR) has been renamed to Magnetic Resonance Imaging (MRI) for the same reason. So maybe we would be better off using “Non-Carbon” instead of “Nuclear” when it comes to generating energy.
Similarly, I think we would be better off if “fat” was not our word for excess weight. Because “fat” is also our term for oil and we naturally conclude that eating oil is fattening. That cholesterol is a kind of fat has made matters even worse. And “calories” have become synonymous with gaining weight, which is another naming mistake. Even the word “weight” is a problem, since you can become skinnier while gaining weight, because muscle mass weights more than the same volume of body fat. Unfortunate names can lead to pervasive but incorrect ideas.
So it may sound wrong, but fat is probably good for you and grain can be bad. And calories turn out to be mostly irrelevant.